Semirigid airship



Feb. 1o, 1925.

G. A. cRoccO smmexn Ansar? Filed sept. 26.*'1922 Patented Feb; 10, 1925.

i rUnl,1ran STATES GAETANO ARTURO CROCCO, OF ROME, ITALY.

SEMIRIGLID AI'RSHIP.

Application filedA September 26, 1922.` Serial No: 590,676.

To all whom. it muy concern Be it 'known that (io-terrano Awful-:o

Cnocco, a subject ofi the King of Italy7 re siding at Rome, in theKingdom Vof Italy, have invented certain vnew and useful Im',-provements in Semirigid. Airships', ofv which the following is aspecification.

The semirigid airships wherein,thelbendL ing and cutting stresses of theloads are bornel by a stiff lower frame owingto this fact lose the chiefadvantage of their'type, ie. their flexibility, and the stiff framewhenl the airship is travelling in exceptionally bad weather, if evenmomentary, is subject 'to break towards its middle.

In order to avoid this inconvenience one or more articulations may beproif'ided 1n the lower frame, where the' bending stresses! due tostatical loads are on the average of little importance and leave thepoints .wherer the joints are tobear the dynamic loads and theoccasionalstatical overloads bythe natural resistance of the envelopeunder pres sure. l

This can beV done `without l any special change in the framesvnow-a-days-:used for semirigid airships, if the airship i's-allowedf,`under the action" of these dynamic `loads' or statical overloads, todeform freely `in `its longitudinal line, owing to the elasticity of thecloth whereof it is made.

In such case, however, `said deformation, thoughit occurs `gradually andsteadiflfyghas the inconvenience to lessen the penetrating quality ofthe airship and `introduce dynamic perturbating actions.

Thus is itnecessary to eliminate it, or at least reduce it to bepracticallyl of little value; and this invention has for itsobjectstructural arrangements designed in View of securing the aforesaidresult.

They consist substantially in rope connections of the hinged sectionscarried out by connecting the ascensional forces acting on the baclcofthe envelope, as it will be better hereunder explained with reference tothe appended drawings wherein:

Figs. l and 2 respectively show in transverse and in a longitudinalsection an airship with connections of the lower beam and the back ofthe envelope;

Fig. 3 shows in a longitudinal section an airship in accordance with theinvention with a lower beam with acentral hinge, and an upturned`c,atenaryas in a suspension bridge connecting the beam with the back ofthe gas bag; l

Fig; il 'shows a longitudinal section of another airship also with asingle central hinge for the beam, but with two catenaries instead' ofone Fig 5 shows, also in longitudinal section, an airship with a doublehinge beam, and with two crossing catenaries;

Figs. 6 and 7 show details of the -ca-tenary attachments.

Assume, by way of instance, it is proposed to render indeformable anair'ship of the ta-lian type, in which the ascensional force` istransmitted to a lower beam not only by means of the tension of thecloth of the gas v bagA on the sides, but also by means of ropeconnections with the back, as shown in Figs. l' and 2.

In-` both figures, l, l, l, is a rigidf frame which, by way of examplehas been illus ti-ated as" a triangular beam; 2, 2, are the sides oftheenvelope which transmit to it partially the lifting power; 3, 3, 3 arerope connections" wliichcollect the lifting power on the back of asection andV transmit it by means of ropes 4, 4, 4 tothe beamunderneath.

Now by introducing (Fig. 3) a hinge 5 towardsthe middle of the beam andconnectw ing' withcatenaries in an inverted suspen-V sion `bridge avpart of the lifting power of the' ropes 4, shows inthe foregoingfiguresq it will' be understood how, by suitably choose ing the extreme;points of attachment 7 of the :catenary and the positions of the loads8,` the `bending momentdue to said loads, to the reactions of thecatenary in the points 7, and to the residual lifting powers transmitted to thebeam by the ropes 4, can be made to vanish.

In this arrangement of things it is of course necessary not to balancewith the catenary all the lifting power of the ropes 4, and to leave aresidual part so as to allow the catenary to eventually be able todevelop a greater tension without its attachment points at the ropes 41giving away.

rFhis happens precisely when through dynamic actions or through staticaloverloads, in the two sections of the beam, on both sides of the hinge,develop forces in a downward direction which by acting on the connectionpoints 7 of the catenary mcrease its tension and therefore take up alarger portion 'of the lifting forcesv of 1. It will be understood how,within the limits of such lifting forces, the system thus constitutedwill not be appreciably deformed, and acquires therefore the capacity ofsustaining eventual loads in the direction as indicated.

It will be also evident how the system lends itself to resist withoutdeformation the action of eventual loads in the opposite direction, viz:in an upward direction.

In such case the tension of the catenary diminishes and therefore theropes 4i increase, to the utmost, the residual lifting power transmittedto the beam; and the limit of indeforn'iability is exactly this maximumwhich corresponds to the vanishing of the catenary tension.

The rope connections above described secure therefore theindeformability ot' the whole structure` of catenary and hinged beam,and hence of all the envelope.

It possesses also the advantage of lessening the weight of the beam, forit substitutes to the fiat beam an element of greater height inresisting to a part of the stresses of pe-rn'ianent loads.

Instead of only one c-atenary, two as 6 and 9 in Fig. t and even moremight be provided and the beam might have two or more hinged joints, 11,1.2 with crossed.' catenaries 13, 13 as in Fig. 5, ditlerently connectedwith one another, according to the opportunities resulting in each casefrom the distribution of the loads.

The details of the connections 'of tie catenaries with the ropes 4l areillustrated by way of example in Figs. 6 and 7.

The vertical ropes 4, double or single, carry an eyelet 19 within whichruns the rope 6 of the catenary. The sliding movement of this rope isprevented by stays 1G adhering to the rope. A little adherence willsuffice because the differential tensions of the rope 6 are a small partof the required tension.

The structure above described constitutes z'. new type of stiifening inairships wherein the envelope concurs to bear the bending stresses ofthe loads. The upper catenary tension and the corresponding compressionof the lower beam resist in every section the statical or dynamicalflections of the loads, forming a. true resisting beam with memberdistant one from the other about the diameter of the section, andtherefore in the best geometrical conditions to obtain the utmostlightness.

Claimsl. ln semirigid airships with a lower frame comprising a pluralityof rigid tions, hinges connecting said sections, and substantiallyvertical rope connections between said sections and the top of theenvelope where the vertical ropes are fastened by means of smallcatenaries, catenary connections in the shape of an inverted suspensionbridge between a plurality of said vertical ropes, and which collect thelifting power from the back of the envelope and transmit it to the rigidsections of the lower frame where their ends are fastened.

En sen'iirio'id airships of the class as specified .in claim 1 and inwhich the lower frame comprises two hinged rigid sections. a. singlelarge catenary connecting the rertical ropes and fastened at each of itsends to one of the sections of the lower frame,

3. In seinirigid airships of the class as specified in claim 1 and inwhich the lower frame comprises two hinged rigid sections` a pluralityof catenaries connecting the vertical ropes and fastened at their endsto each ol tlie'said two sections.

4i'. .ln scmirigid airships of the class as specified in claim 1 andwith a lower rigid frame comprising three hinged sections. catenariesconnecting the vertical ropes` each catenarv fastened at its both endsto two of the hinged sections.

In testimony whereof I have signed my name in the presence of twosubscribing witnesses at Rome in the Kingdom of -Italy this 7th day ofSeptember, 1922.

GAETA NO A RTURO CR OCC() lVitnesses ANToNio Lotvnooon'rra. VVILHnmrScrutin.

